Shape memory alloy control

Fair-play

Hi there


Im a MENG student (In England)·doing a group project·designing a·robot arm, including the hand in the style of a human arm.·We are using shape memory alloys to provide the movement·for this and although i have used a basic stamp before have·i have never attempted any kind of power control·using it. I·have a few questions if anyone·may have any ideas·etc would be much appreciated!

The power source is 12v DC

1)-The arm will need to switch 20amps for the bicep muscle·has anyone got any good ideas for switching circuits or know were i may be able to look one up?

2)-Any recomendable of the shelf solid state relays to switch 20 amps

3)-Also some smaller loads between 2 and 10 amps will need switching any advice on circuits etc greatly accepted

4)-Would you recommend using the PWM output or the pulsout for providing a variable switching control?

Thanks for any help

Tim




·

metron9

Google is your friend Search: "Solid State Relays"
First hit
http://www.sordselectric.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=SE&Category_Code=SSRHS

Dont know what you mean
"variable switching control?"

LoopyByteloose

I think you don't want to use solid state relays.· Generally they are made for AC current.· Though there are some DC current ones, you are adding a bit of expense to your design and they are less available.

You can use MOSfets that are rated for very high voltages and very high current. These can actually be driven from TTL level signals and run very cool.· [noparse][[/noparse]I think you can even use a few in parallel to gain enough current]

If you are concerned about damaging the BasicStamp you can isolate the output with a 74HC07 for six lines [noparse][[/noparse]very cheap] or you can use opto-isolators to be assured complete separation of circutry.

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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

Paul Baker

Kramer said...

·[noparse][[/noparse]I think you can even use a few in parallel to gain enough current]

You are correct Kramer.

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·1+1=10

KenM

http://glitchbuster.com/

IRL520N, IRL530N, and IRL540N will easily interface with your stamp and switch a high current.

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Ken